Pultruded profiles, organic sheets, hollow bodies and containers, as well as semi-finished materials with reinforcing fiber fabrics, braids, weaves, knits, embroideries, non wovens, fiber bundles and rovings, etc. embedded in a thermoset matrix, for example of polyester or epoxy resin, have found various uses in a growing market.
Such composite parts with a matrix which completely encloses the textile reinforcement, show good dimensional stability and their properties are to a large degree unsensitive to moisture; they show a high resistance against aqueous systems, greases, oils, motor fuels and alcohols, and resist environmental effects with a sufficiently good thermal resistance.
A basic principle for their production therefore is as perfect as possible an impregnation of the textile reinforcement structures by the resin in the liquid state with subsequent shaping and curing, preferably by the effects of heat and pressure.
However, postforming, which is often necessary, is not possible for the thermoset matrices.
In producing composite materials with a thermoplastic matrix, the high matrix viscosity makes difficult the complete wetting and impregnation of the reinforcement structure.
In spite of the application of heat and pressure, the reinforcement fibers are often insufficiently embedded and gas inclusions might not be completely eliminated.
A method for producing cast molded bodies from anionic polymerized lactam, particularly lactam-6, containing a filler material, is described in German Patent Publication DE-A-28 01 990. The filler materials admixed with the lactam melt are intended to reduce the interfering large shrinkage of the formed bodies, known in connection with cast polyamides. It should be noted that, in accordance with the well-known prior art, the activated, anionically catalyzed lactam polymerization is here performed by using two separate lactam melts, one of which contains the catalyst and the other the activator.